Moreover, to complete the picture of nanoscale organic electronics, we investigate the feasibility of the rotaxane molecular memory reported by Heath and Stoddart in 2002. In particular, its switching performance is probed theoretically through the evaluation and estimation of the energy landscape, the ionization potentials and the dielectric constants. However, it is found that the switching time of this molecule is greatly limited by an intrinsic "shuttling" reaction to merely 3.7s under most conditions. Additionally, an alternative switching mechanism is proposed based on the new theoretical findings. With the successful deciphering of the information hidden behind the GIXD and the lucrative enhancement in physical understanding of the rotaxane molecule using first principles calculations, further effort is invested in exploiting this computational technique to predict candidate molecules that display desirable functionalities. Several halogenated acene molecules are expected to pack in the face-to-face motif, in contrast to the commonly observed herringbone packing motif. This is believed to enhance the mobility. Synthesis of these candidate molecules is underway to allow experimental verification, with the goal of dramatically improving device performance to fully exploit the idealized electrostatics of these structures.